Clement l



- only to have no free acid present, but to add SAES CLEMENT L. PERKINS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO METALS RECOVERY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE.

FLOTATION OF MINERALS.

No Drawing.

To all whom it may concern:

Be it known that I, CLEMENT L. PERKINS, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny, State'of Pennsylvania, have invented certain new and useful Improvements in the Flotation of Minerals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

' This invention relates to the concentration of'minerals, such as sulfid ores and the like, (for example, chalcopyrite with a $111- cious gangue), by flotation, and is based upon the discovery that improved results can be obtained by carrying out the flotation operation with the addition to the ore or oughly and uniformly distributed throughout th ore pulp. The mixture is then sub jected to a flotation operation as in anordinary Callow cell or in apparatus where the air is incorporated in the ore pulp by mechanical agitation. With some ore pulps it may be desirable to add either small amounts of acids or of alkalis, depending upon-the nature of the' ore pulp to be treated, but in general free acid should not be present to any appreciable extent when the toluidin-is added.

" With some ore pulps it is important not suflicient free alkali to give a distinct alkaline reaction to the ore pulp during the flotation operation. Small amounts of caustic alkali, such as sodium hydrate, or of alkali salts, such as sodium carbonate, may thus be added, in regulated amounts, to give the ore pulp the proper degree of alkalinity,

The amount of toluidin used may vary somewhat, for example, between one-half pound orless and one and one-half pounds Specification of Letters Patent.

of the para-toluidin and ortho-tolui- Patented Nov. 25,1919.

Application filed July 2, 1919'. Serial No. 308,321.

per ton of ore (that is, calculated on the weightof the ore and not of the ore pulp).

The invention will be further illustrated by the following specific example: 500 parts byweight of ore was ground in the ball or pebble mill with 250 parts of water, sodium hydroxid in amount equivalent to two pounds per ton of ore, and commercial mixed toluidin equivalent to one pound per ton of ore. The resulting pulp was placed in a Callow pneumatic rougher cell, together .with sufficient water to form a free-flowing pulp, and then subjected to a flotation treatment. The ore treated contained about 1.42 per cent. of copper. The concentrates produced contained about 15.4: percent. of 00p per, and the recovery of the copper was about 87 per cent.- The ore treated was a Utah copper ore.

With ores of the character above referred 'to, the use of alkali is. not necessary, but its use has been found to greatly improve the recovery.

Comparative results obtained With the use of ortho-toluidin or para-toluidin, and mixed toluidin, composed mainly of the manner similar to the specific example given above, gave the following result:

Heads. Conots. Recovery.

Orthotoluidin 1.38 13. 7 7s. 2 Paratoluidin 1.38 19.9 86.4 Mixedtoluidin 1.38 16.5 81.4

It is characteristic of the invention that the froth obtained is readily broken up and the toluidin recovered therefrom so that it is available for use in the treatment of further amounts of ore. That is to. say, the air-- cuit water recovered from the concentrate concentrates obtained and the resulting con-- centrates can be muchmore easily separated by filtration than the common concentrates obtained by the use of oil as the flotation agent. The action'of the toluidin may, however, be modified or supplemented by adding ortho .and para-toluidm, carried out 1n a 3 other agents (such as oils or non-oleaginous agents) which promote the flotation .and which do not prejudicially affect the action of the toluidin.

In applying the toluidin, it may be introduced into the tube mill in which the ore is being ground, or it may beotherwise introduced into the ore pulp in any suitable way, asjrior instance, by dropping it into the ore pulp before it enters the flotation cell, or by first digesting it in hot water and mixing the product with the ore pulp just before it enters the flotation cell.

What I claim is: 1. The method of efle'cting the concentration of minerals by flotation, which com-.

prises adding to the mineral pulp a small amount of toluidin, and subjecting the resulting mixture to a flotation operation; substantially as described.

2. The method of effecting the concentration of-mineralsby flotation, which com- 3. The method of eflecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of toluidin and sufficient alkali to give the ore pulp a distinct alkaline reaction,

and subjecting the resulting mixture to a flotation operation; substantially as described.

4:. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp'a small amount of toluidin and of oil, and subjecting the resulting mixture to a flotation operation; substantially as described.

In testimony whereof I aflix my signature.

CLEMENT L. PERKINS. 

